Inventories - Inventory due to contract changes, negotiated settlements and claims for unanticipated contract costs (Details) - USD ($) $ in Thousands |
Sep. 30, 2016 |
Dec. 31, 2015 |
|---|---|---|
| Inventory Disclosure [Abstract] | ||
| Contract changes, negotiated settlements and claims for unanticipated contract costs | $ 4,077 | $ 7,137 |